.nav a{
	display:inline-block;
	font-size:12px;
	width:50%;
}
.tupian{
	position: absolute;
	width:150px;
	height:150px;
	top:0;
	left:0;
	bottom:0;
	right:0;
	margin:auto;
	display: none;
}
#loading_img{
	position: absolute;
    width:50px;
    height:50px;
    top:0;
    left:0;
    bottom:0;
    right:0;
    margin:auto;
}
